Jelly Fishes. 609 



to the orifice of the month, and swallowed without 

 mercy. 



One of the commonest kinds of these Polyps is the 

 Mesembryanthemum (Actinia Mesembryanthemum), a large, 

 usually liver-coloured species, with a row of blue warts 

 round the margin just outside the tentacles. It is found 

 abundantly on the rocks of our Southern coast especially. 

 The Thick-horned Anemone (Actinia or Brusodes crassi- 

 cornis) is another large and fine species, usually of a red 

 colour, with very thick tentacles, which are generally 

 white with pinkish bands. The Sea Cereus (Anthea 

 Cereus) has long slender tentacles, which are not retracted 

 in the same way as those of the Sea Anemones generally. 

 The tentacles are usually tipped with a pink or purple 

 tint ; they are constantly waving about in the water in 

 search of prey, and instantly seize upon any creature 

 that passes over them. The Parasitic Anemone (Actinia 

 parasitica) and the Cloak Anemone (Adamsia palliata) 

 always attach themselves to univalve shells which are 

 occupied by Hermit Crabs. 



JELLY FISHES. 



THE animals commonly known as Jelly Fishes are free- 

 swimming Eadiata ; they were described by Cuvier and 

 most succeeding naturalists under the name of Acalephce, 

 from a Greek word signifying " nettles," because many of 

 them produce a stinging sensation when they come in 

 contact with the skin. Their name in several languages 

 signifies " Sea Nettles." The Acalephas of Cuvier are 

 now regarded as belonging to the same class as the 

 Hydroid Polyps. 



The common Medusa (Medusa amita), which may serve 

 as an example of this group, is found in great abundance 

 round our coasts ; it is of a circular form, convex above, 

 concave beneath, like an umbrella, the stick of which is 

 represented by a thick stalk, containing the mouth and 

 stomach, and terminated by four long arms for seizing 

 the animal's food. The skin of these, and of the body 

 and its appendages generally is full of the thread-cells 



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